System uses following modules:

better_formats, better_messages, captcha, CCK, dst, filefield, imageapi, imageapi_gd, imagecache, imagecache_ui, imagefield, lightbox2, no_anon, pathauto, persistent_login, tagadelic, token, uploadpath, wysiwyg, admin_menu

So if you want create normal translation for installer to get translated version of software out  of the box -you need  translations for modules located in their folders(needed for correct import).